How to learn to fix mobile using diagram

In this tutorial I will teach you how to learn to fix mobile using diagram. Reading schematic diagram is a must have skills every technician should concentrate on learning.

For demonstration purposes I will teach to how to repair a no power Nokia.

Upon receiving the cellphone from the customer I ask basic questions to identify where in the phone is the problem.

1. What is the problem of the cellphone?
ans. It wont power on but I notice it is charging.

From the question I made and the answer from the customer I suspect that there is an open circuit from the power on signal coming from the switch to PWRONX of the power IC or UEM.

Now is the time to trace where is the open pattern. You see technicians must have a skill in reading mobile diagram.

Here is the basic step how to learn to repair using cell diagram.

Procedure:

1. Identify the components.

 

 2.  Now we can determine the different component to work on are:

S302- SWITCH

C310- CAPACITOR

R306- RESISTOR

3.  Next is read the equivalent schematic diagram.

4.  From the schematic diagram above in order for the cell phone to power on you need to push the switch to trigger the PWRONX of the power supply.  After you push the switch the signal will travel from switch to R306 to PWRONX of the UEM.

5.  Using your VOM you need to test the switch if it is good.  Next is test the resistor.  Upon testing the two components I notice that the resistor is open.  It wont give me any resistance reading.

6.  Replace R306 using the same value and component from another or the same mobile board.

7.  Assemble and test now you can power on your cell phone.

In this tutorial you gain the knowledge how to learn to fix mobile using diagram.

Do you want to learn more?

Start my:  Mobile phone repair training